Comment 2 for bug 168044

I'm afraid this is a GTK bug. We don't do anything
nonorthodox here. Just a slider and a spinbutton attached to
a common GtkAdjustment. We do not touch any signals except
value-changed on adjustment. Yet GTK tries for some reason
to blink the spinbutton cursor while the screen is updating,
and focus is not there already, so it crashes.

By the way it has nothing to do with blur as such. The same
thing happens with Opacity too, only rarer because opacity
screen redraws are usually faster. But if you change opacity
of a complex large object, you can get it to crash in the
same way.